SLApps Sonic Learning Applications: systematic exercises for developing listening skills in electroacoustic music

F. Liszt Academy of Music, Budapest
2120 Dunakeszi, Berzsenyi D. u. 14/A

This article presents the results of a research aiming to develop a series of ear-training exercises for electroacoustic musicians. The 18 month-long project was funded by the Social Renewal Operational Programme of the Government of the Republic of Hungary.

After the sonic revolution in the second half of the 20th century, a rapid development of the material constituting music took place. A new music ``lexicon'' has been formed, where the significance of so called primary musical parameters ceased to exist, and timbre became an integral part of the creation of musical form. The timbre of sound became a new form-bearing quality of music. Timbre is nevertheless a substantially more complicated parameter than pitch or rhythm since it is multidimensional and has an indefinable – theoretically infinite – range. Its methods of organization cannot be described by the rules of traditional music theory. Along with the expansion of the electroacoustic music repertoire, many contributions have been made to form its own theory. In the process of the development (and later in the process of the application) of a new music theory, it is indispensable to rely on common listening experiences collected and shared by the music community. To embrace and describe the newly discovered sonic material, composers and researchers still rely, on the one hand, on Pierre Schaffer’s and Denis Smalley’s systems of categorization and, on the other hand, technical description of sound synthesis and processing techniques. Reading analyses of electroacoustic music pieces, one can also see different graphic representations of sonorities very often based on sonograms. None of the above mentioned methods allow for univocal description of the basic elements of the sound material used in electroacoustic music compositions. Electroacoustic music is still lacking a standardized system similar to the classical music solfége, where the basic form-bearing qualities - pitch and rhythmic elements - are specified and expected to be recognized by professional musicians. Development of a standardized ear-training system dealing with timbre would help to:

SLApps are developmental series of exercises that enable students to acquire analytical listening skills, remember and understand timbre. SLApps are downloadable standalone programs (built in MAX/MSP) containing practical interactive applications that allow direct learning experience and a possibility to test and assess these newly gained listening skills.

SLApps extend the notion of ``ear training'' to those qualities of sound that cannot be quantified in terms of pitch and rhythm. The main subject of exploration are the manifold dimensions of timbre space. The practical work of the creation of the exercises was informed by my research on the control of the multidimensional timbre space documented in my DLA dissertation3.25. In my thesis, I introduced the concept of ``Reduced Timbre Space''. Reduced timbre space consists of a matrix containing a limited amount of sensory dimensions with a limited range. The reduction concerns the number of dimensions, their range, the function of mapping, and the number of discrete steps within the dimensions. The conceptual apparatus of the reduced timbre space is well applicable in practice through the construction of audio engines that enable the manipulation of varying numbers of timbre dimensions. Each SLApp is a realization of a reduced timbre space. By separating, identifying, and scaling timbre dimensions, sounding materials of varying complexity can be created. Their structure is made visible by structuring and visualizing the parameters of the sound synthesizing and processing techniques.

It was necessary to employ a variety of sound synthesis and processing techniques in order to model timbre dimensions. Whilst different methods of synthesis and processing can create identical ``fixed coordinates'' within timbre space, the trajectories between ``coordinates'' are different for each synthesis technique. The choice of a particular method will determine which paths one can follow through multi- dimensional timbre space. For example, modifying brightness with a low-pass filter will affect change on both the ``hollow'' (clarinet-like sound: realized by adding together odd partials) and the ``nasal'' (oboe-like: realized by adding together all partials) dimensions. The synthesis techniques used in the exercises include: additive synthesis, FM synthesis, subtractive synthesis, and granular synthesis.

The exercises are devised developmentally, through gradually increasing the number of timbre dimensions and the complexity of tasks over consecutive steps. Initially, students are asked to identify and recognize 5-7 steps along one single timbre dimension. The most complicated exercise in the recent version combines six timbre dimensions containing a matrix of 1800 sounds. The tasks include identifying the dimensions of individual sound objects, identifying envelopes of synthesis and processing parameters influencing timbre dimensions, identifying and recreating timbre motifs (Klangfarben melodies) and recreating timbres themselves.

Some of the more complex SLApps are based on outstanding researches and pieces of electroacoustic music (e.g. works by John Chowning and Jean-Claud Risset).

List of SLApps:

  1. changing timbres along the darkness-brightness dimension applying low-pass and high-pass filters
  2. changing timbres along the noisy-pitched and darkness-brightness dimensions applying band-pass filter with a bandwidth of octave and third
  3. changing timbres along the dimension of brightness by adding 8 sinewaves
  4. changing timbres along the brightness, nasal and hollow dimensions in different pitch registers by adding together 48 sinewaves
  5. changing timbres along the metallic, sharp-soft attack dimensions by FM synthesis
  6. changing the hardness of the attack and the noisiness of a percussive sound by FM synthesis
  7. changing the timbre along dimensions of noisiness, sharpness by FM synthesis
  8. changing the timbre along resonance, noisiness and brightness by additive resonant filter
  9. changing timbres along the beating-rough-inharmonicity dimension by adding beating sinewaves to the spectrum
  10. changing the behaviour of grains by granular synthesis
  11. changing sounds along the dimensions of the speed of granulation and brightness creating interpolating timbres by applying envelopes to the parameters.
  12. modeling timbres based on Jean-Claud Risset’s synthetic bell sound applying six different dimensions
Each SLApp contains demonstrations and tests of different difficulty. The project is a work in progress. The existing SLApps have been tested in education at courses for electroacoustic music composers at the F. Liszt Academy of Music and at Pécs University.


... dissertation3.25
Szigetvári, A. 2013. ``A multidimenzionális hangszíntér vizsgálata'' (In Hungarian. Translation of title: Multidimensional Timbre Space) DLA thesis, F. Liszt Academy of Music, Budapest, pp. 220
adrian 2015-06-03